This invention relates to knit fabrics having contrasting appearance between the technical face and the technical back.
Nappable knit fabrics have been made on double needle bar knitting machines using five to eight yarn guide bars for simultaneously knitting two fabric layers joined by interconnecting pile yarns. After knitting, the fabric layers may be separated by cutting the interconnecting pile yarns. In some knitting processes, the pile yarns are carried by the middle or inner bars (for example, bars three, four and five on a seven bar arrangement) and tie the two fabric layers together, with the pile yarns disposed on the technical back of each fabric. In such fabrics, the pile yarns are employed to provide the fabric with a particular characteristic and aesthetic value such as pattern, softness, luster, hand, resiliency, fullness, bulk and warmth. The pile yarns generally do not contribute to the dimensional stability and strength of the fabric; rather, the backing and stitch yarns, which are generally thinner and less bulky than the pile yarns on the middle bars, provide structural characteristics, e.g., by holding the fabric together and providing dimensional stability. In such fabrics, the technical face of each fabric layer is not nappable by itself, but napping can be achieved by pulling pile yarn from the technical back, resulting in a velour finish on the technical face with the same pattern and composition as the velvet finish on the technical back.
In other knit fabrics, e.g. as described in U.S. Pat. Nos. 6,196,032 and 6,199,410, the complete disclosures of which are incorporated herein by reference, the backing or stitch yarns are relatively heavier than in the fabric layers described above, and they cover the pile yarns at the technical face, so the backing or stitch yarns can be napped to provide fibers for the velour finish on the technical face. As a result, the technical face can have a pattern, e.g. of shapes and/or color, different from a pattern of shapes and/or color on the technical back.
The inventor has found that fabrics having particularly desirable aesthetic properties can be produced, using the methods described in U.S. Pat. Nos. 6,196,032 and 6,199,410, by selecting the pile yarns and the backing or stitch yarns to provide a contrasting appearance between the technical face and technical back of the fabric. For example, the technical face and technical back may exhibit different depths of color. The contrasting appearance is provided by the selection of contrasting yarns for the pile and for the backing/stitch yarns. The contrasting yarns may exhibit, for example, physical differences, e.g., after heating during the dyeing process, and color differences, e.g., due to differences in the amount of dye taken up by the respective yarns. The fabric structure described in U.S. Pat. No. 6,196,032 is utilized to keep the pile yarns to the technical back and the backing/stitch yarns to the technical face and thereby to create the contrast between the opposite surfaces of the fabric.
In one aspect, the invention features a method of making a fabric on a double bar knitting machine, with the fabric having a technical face with a velour surface and a first set of appearance characteristics, and the fabric having an opposite, technical back with a velvet surface and a second set of appearance characteristics, the first set of appearance characteristics of the technical face contrasting to the second set of appearance characteristics of the technical back. The method includes: (a) selecting backing or stitch yarns and selecting pile yarns to provide the fabric with the technical face having the first set of appearance characteristics and the technical back having the contrasting second set of appearance characteristics; (b) knitting a three-dimensional fabric structure on the knitting machine, the structure having two fabric substrates formed from the backing and stitch yarns, each defining a technical face and a technical back, and a plurality of the pile yarns extending between and interconnecting the fabric substrates; (c) during knitting, causing the backing yarns or the stitch yarns to cover the pile yarns at the technical face of each fabric substrate; (d) cutting the pile yarns to separate the fabric substrates, with ends of the pile yarns extending from the technical back of each fabric substrate; (e) dyeing the fabric substrate; (f) processing the backing yarns or the stitch yarns covering the pile yarns at the technical face of the fabric substrate to form the velour surface; and (g) processing the pile yarns at the technical back of the fabric substrate to form the velvet surface. The first and second sets of appearance characteristics are each selected from among: depth of color upon dyeing, degree of raising, degree of air permeability, susceptibility to selected dye formulation, reaction to heat, and degree of coarseness, bulk and/or denier.
Some implementations may include one or more of the following feature. The step of dyeing the fabric may include dyeing to a solid color, and the step of selecting the yarns may include selecting the yarns to have different dyeabilities and/or dye uptakes. The step of dyeing the fabric may include dyeing the backing yarns or stitch yarns exposed at the technical face to have a first base color and a first depth of color and dyeing the pile yarns exposed at the technical back to have a first base color and a second depth of color, the first depth of color being in contrast to the second depth of color. The step of selecting the first set of appearance characteristics and selecting the contrasting second set of appearance characteristics may include selecting the depth of color upon dyeing, with the first depth of color selected to be relatively lighter than the second depth of color. The step of selecting the first set of appearance characteristic and selecting the contrasting second set of appearance characteristics may include selecting the depth of color upon dyeing, with the first depth of color selected to be relatively darker than the second depth of color. The step of selecting the first set of appearance characteristics and selecting the contrasting second set of appearance characteristics may include selecting a first dye for the backing or stitch yarns and selecting a second, different dye for the pile yarns. The step of selecting the first set of appearance characteristics and selecting the contrasting second set of appearance characteristics may include selecting a first material for the backing or stitch yarns and selecting a second material for the pile yarns. The step of selecting the backing or stitch yarns and selecting the pile yarns may include selecting the first material and the second material to be 100% polyester. The step of selecting the pile yarns may include selecting first pile yarns having first appearance characteristics and selecting second pile yarns having second appearance characteristics different from the first appearance characteristics. The step of knitting may include disposing the pile yarns in a predetermined pattern comprising one or more regions of the first pile yarns having the first appearance characteristics and one or more regions of the second pile yarns having the second appearance characteristics different from the first appearance characteristics. The step of processing the pile yarns may include causing the velvet surface to have a depth in the range of about {fraction (2/32)}-inch to about {fraction (18/32)}-inch. The method may further one or more of the following steps: dyeing one or more regions of the backing or stitch yarns at the technical face through by application of dye of contrasting color by wet printing techniques; applying a chemical binder upon one or more regions of the backing or stitch yarns at the technical face to create regions of enhanced surface abrasion resistance; and applying a chemical resist upon one or more regions of the backing or stitch yarns of the technical face prior to the step of processing, for local resistance to napping and raising, thereby to create a predetermined pattern of regions of low or no fleece among adjacent regions of high fleece in the velour surface of the technical face.
In another aspect, the invention features a fabric including a plurality of backing or stitch yarns cooperatively knitted together and thereby defining a technical face with a velour surface and a first set of appearance characteristics, and a technical back with a velvet face and a second set of appearance characteristics, the first set of appearance characteristics contrasting with the second set of appearance characteristics. The fabric also includes a plurality of pile yarns extending from the technical back and being napped or raised, thereby forming the velvet surface at the technical back, the backing or stitch yarns covering the technical face and being napped or raised, thereby forming the velour surface at the technical face. The backing or stitch yarns cover the pile yarns in a manner such that only the backing or stitch yarns are raised along the technical face, and are formed of materials having the first set of appearance characteristics selected from the group of appearance characteristics consisting of: depth of color upon dyeing, degree of raising, degree of air permeability, susceptibility to selected dye formulation, reaction to heat, and degree of coarseness, bulk and/or denier. The pile yarns are formed of materials having the second set of appearance characteristics selected from among the group of appearance characteristics consisting of: depth of color upon dyeing, degree of fiber straightness, degree of fiber curl, degree of fiber shrinkage, degree of fiber crimp degree of raising, reaction to heat, degree of yarn coarseness, bulk and/or denier.
Some implementations include one or more of the following features. The backing or stitch yarns may have a first cross-section and the pile yarns may have a second, different cross-section. The pile yarns may have a cross-section selected from the group consisting of serrated ribbon and trilobal. The backing or stitch yarns may have a first denier and the pile yarns have a second, different denier. The technical back and the technical face may be of the same hue. The technical back and the technical face may have contrasting surface textures. For example, the technical back may have a raised pile surface and the technical face may have a sheared chamois or suede surface. The velvet surface of the technical back and the velour surface of the technical face may have contrasting pile heights. For example, the velvet surface may have a pile height in the range of about 0.06 inch to about 0.6 inch, and the velour surface may have a significantly lower pile height. The backing or stitch yarns may include microdenier yarns. The fabric may be jet-dyed. The pile yarns, backing yarns and/or stitch yarns may include polyester, e.g., they may be 100% polyester yarns. One or more regions of the velour surface may have a color contrasting to a surrounding region by application of dye by wet printing techniques. One or more regions of the backing or stitch yarns at the technical face have enhanced surface abrasion resistance by application of chemical binder. The technical face may define a predetermined pattern of regions of low or no fleece among adjacent regions of high fleece in the velour surface, achieved by application of a chemical resist upon regions of the backing or stitch yarns of the technical face prior to processing, for local resistance to napping and raising.
In some implementations, the fabrics exhibit one or more of the following advantages. The technical face may have a high cover factor and very fine denier, and thus exhibit good wind resistance. The technical face may provide low air permeability. The technical back may include a raised surface that is configured to provide a high level of thermal insulation to reduce convective heat loss. For example, the technical back may have a high pile height, e.g., in the range of 0.06 inch to 0.6 inch.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features and advantages of the invention will be apparent from the description and drawings, and from the claims.